Background & Aim: Pap smear test is an easy and low cost screening method for prevention of cervical cancer. Attempts to improve the quality of this test have an important role in early diagnosis and treatment of the disease. The purpose of this study is determination of differences between cervix brush and modified Ayre spatula in terms of cervical smear adequacy. Patients & Method: In a two-group randomized trial, two hundred forty women undergoing cervical smear at the gynecology clinic of Air Force Hospital were randomly assigned to two groups of cervix brush and modified Ayre spatula, each with 120 cases. The cytopathologist was blind to the cervical smear collection device. Bethesda system guideline was used and smears were considered either satisfactory or unsatisfactory accordingly. Results: The findings showed no significant difference between capability of cervix brush and modified Ayre spatula to produce satisfactory and unsatisfactory smears(p=0.497). Conclusion: Both methods are recommended to be used in health centers with emphasis on training medical personnel to take pap smears with special care. Comparison of the two mentioned devices regarding the detection of precancerous lesions in high risk women is recommended for further studies.